Utilization of Deposited Coke on Zeolites During the Catalytic Cracking of Nitrogen-Containing Polymer for the Oxygen Reduction Reaction

Abstract

This work focuses on the development of a new method to utilize deposited coke on zeolite catalysts, formed during the plastic waste cracking. Nitrogen-doped carbon catalysts are prepared using nylon-66 and Zn2+ ion-exchanged ZSM-5 zeolites. After the cracking reaction, nitrogen-doped carbon materials are obtained by removing zeolites from zeolite/coke composites using base and acid treatment. The synthesized N-doped carbon using Zn2+ type ZSM-5 zeolites exhibits higher catalytic performance on the oxygen reduction reaction (ORR) with an onset potential of 0.95 V (vs RHE) and a half-wave potential of 0.80 V (vs RHE) than that using H+ type ZSM-5 zeolites. The characterization revealed that the evaporation of Zn2+ in zeolites significantly enhanced the porosity of N-doped carbon. Moreover, the aromatization and poly-cyclization reactions promoted the generation of highly active edge Valley-N sites, leading to their outstanding activity on ORR. This work provides new directions for the utilization of deposited coke on zeolites.